F2 is aserine protease protein that in humans is encoded by the F2 gene. Prothrombin(coagulation factor II) is proteolytically cleaved to form thrombin in thefirst step of the coagulation cascade, which ultimately results in thestemming of blood loss. F2 in turn acts as a serine protease that convertssoluble fibrinogen into insoluble strands of fibrin, as well as catalyzingmany other coagulation-related reactions.